Work feeding means for sewing machines

ABSTRACT

For enabling a presser foot more effectively to cooperate with work feeding means such as a conventional dog, an auxiliary presser engageable with the presser foot is automatically actuated, at least for an initial portion of a sewing run, to cause the work to be uniformly fed to the needle of a sewing machine. The auxiliary pressure is attachable to most sewing machines and, while operable on single ply work, is likely to have particular advantage in feeding irregular or bulky items such as hems, binding, trimming or the like.

United States Patent Wickers et al.

[ 51 May 30, 1972 [54] WORK FEEDING NEEANS FOR SEWING MACHINES [72]Inventors: Francis A. Wickers, Beverly; David W. France, West Newbury;Ronald C. Mason,

Hamilton, all of Mass.

[73] Assignee: USM Corporation, Boston, Mass.

[22] Filed: Sept. 14, 1970 [2l] Appl. No.: 71,647

[5 l Int. Cl. v ..D05b 29/00 [58] Field of Search ..112/212, 235, 236,240

[56] References Cited UNITED STATES PATENTS 3,002,477 10/1961 Silberman..l 12/235 3/1960 lsler ..l 12/235 Laidig ..l 12/235 PrimaryExaminerPatrick D. Lawson Attomey-Richard A. Wise, Richard B. Megley andCarl E. Johnson [57] ABSTRACT For enabling a presser foot moreefiectively to cooperate with work feeding means such as a conventionaldog, an auxiliary presser engageable with the presser foot isautomatically actuated, at least for an initial portion of a sewing run,to cause the work to be uniformly fed to the needle of a sewing machine.The auxiliary pressure is attachable to most sewing machines and, whileoperable on single ply work, is likely to have particular advantage infeeding irregular or bulky items such as hems, binding, trimming or thelike.

5 Claims, 4 Drawing Figures Patented May 30, 1972 3,665,877

2 Sheets-Sheet l inventors Francis AlWicke-rs David WF'rance Fonalr] 6.Mason v55/ their A [[07'1'16'7 Patented May 30, 197-2 3,665,877

2 Sheots-Sheet 2 WORK FEEDING MEANS FOR SEWING MACHINES BACKGROUND OFTHE INVENTION As a work piece is first advanced from an initialrelatively static position toward the sewing instrumentalities of asewing machine, it is likely to require the application of more feedingforce than subsequently when a remaining length is to be fed and feedingis in progress. More especially, it is found that hard or bulky work tobe sewn, such as hems or binding comprising more than a single ply,require a more positive feeding force to be applied when the work firstreaches a stitching locality. In the absence of a means to enable aconventional presser foot and feed dog to effectively cooperate, thework may remain stationary and/or'it may be unduly stretched orotherwise deformed before the desired uniform rate of feeding isattained.

In some sewing machines of the prior art the problem of uniformlyfeeding the upper and lower ply simultaneously has been met to someextent, for example, by the provision of an upper as well as a lowerserrated feed dog and a presser foot. This involves employingcomplicated actuating mechanism in a rather crowded operating area, andentails application of positive feeding force when that may beunnecessary, or the continuous exertion of greater presser foot dragthan may be desirable.

SUMMARY OF THE INVENTION In view of the foregoing it is an object ofthis invention to provide an improved automatic work advancing mechanismfor a sewing machine or the like. More particularly it is an object ofthis invention to provide a versatile device in a sewing machine forincreasing the effectiveness of its feed mechanism, for example, a feeddog in at least a starting portion of each run.

Another object of the invention is to provide, in a sewing machinehaving a four-motion feed dog and a cooperative presser foot, animproved means for automatically urging the presser foot and the feeddog into closer relation as the first I or 2 inches of a workpiece areadvanced past a needle.

To these ends, and in accordance with a feature of the invention, thereis provided in a sewing machine, in combination with a pivotal presserfoot and cooperative feed means such as an orbital feed dog, a presserfinger engageable automatically with the presser foot for apredetermined interval to insure that the feed dog can effectivelyexert-force to commence advancement of the work piece to be sewn. Asherein shown the feed finger preferably is in the form of a rubbertipped piston rod adjustably mounted for engagement with a selectedupper portion of a presser foot, the latter being yieldingly urgeddownwardly and being acted on by a spring for tilting the heel of thefoot into initial bed engaging relation while its toe portion isinclined upwardly to permit reception of the edge of the work piece tobe fed. Also, as herein shown, a control circuit including sensing meansis employed for automatically starting the sewing machine and applyingthe auxiliary presser finger to urge the feed dog downwardly intosubstantially parallel relation to the bed of the machine during a firstportion of the sewing run.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features ofthe invention will now be more particularly described in connection withan illustrative embodiment and with reference to the accompanyingdrawings thereof, in which:

FIG. 1 is a perspective view of a portion of a sewing machine adapted toperform hemming, a presser foot and auxiliary presser finger being intheir raised or inoperative starting positions as a work piece is movedinto a hemming device;

FIG. 2 is a schematic diagram of a control circuit provided for themachine of FIG. 1;

FIG. 3 is a perspective view similar to that of FIG. 1, on a largerscale, and showing the feeding means in operative relation to the workpiece; and

FIG. 4 is an enlarged detail view in front elevation and partly insection showing a hem being fed.

Referring first to FIGS. 1, 3 and 4, a sewing machine generallydesignated 10 has a head 12 and a work supporting bed 14. The head isprovided with stitch forming instrumentalities including a reciprocableneedle 16. The machine further includes work feeding mechanism hereinshown as a four-motion feed dog 18 operating in conventional manner in aslot in the bed 14 for cooperating cyclically with a presser foot 20.The latter is supported by a presser bar 22 which is reciprocableheightwise and yieldingly urged downwardly by means not shown.Preferably a compression spring 24 (FIG. 1) is disposed between a latermentioned bracket 26, adjustably secured by a clamp screw 28 to the bar22, and a heel portion of the presser foot to yieldingly tilt its toeend 30 upwardly from the bed 14.

The bed 14 is provided, for purposes of this illustration, with a flat'extension 32 fitted with one or more hemming devices 34, 36, but it willbe understood that application of the invention is not thus limited buthas general utility in more effectively feeding any flexible work pieceswhich, by reason of their hem, ornamentation, or other materialcharacteristic, tend to provide added resistance to smooth, uniformfeeding. A work piece W which is to have a hem H (FIG. 3) formed andthen secured, as by stitching in the machine 10, may initially beintroduced edgewise to the devices 34, 36 either manually or by anautomatic feeder of the type which, for example, employs a reciprocablepick-off 38 shown in dash-lines in its delivery position in FIG. 1. Thedevices 34, 36 may also be hemmers of any suitable type including forinstance those having a pneumatic in-feed and fully described incopending applications, Ser. No. 6,510, filed Jan. 28, 1970 in the nameof Richard W. Gray, and Ser. No. 9,185, filedFeb. 6, 1970 in the name ofPaul E. Morgan. It will be understood that the hemmers 34, 36 arealigned to provide a folded margin in the work parallelto the line offeed and stitching to be performed. A sensor 40 (FIGS. 1 and 2), whichmay be of any suitable type and is herein shown as fluidic, is disposedto straddle an orifice 42 formed in the extension 32. The arrangementdesirably is such that introduction of the work to the hemmers 34, 36intercepts a low pressure jet of air continuously flowing in the sensor40 thereby, after a suitable interval allowed for hemming as determinedby a time delay mechanism 44 (FIG. 2), signaling a fluid amplifier 46which opens a valve 48 to allow pressure from a higher pressure line 50to lower the bar 22 and the presser foot 20, first into tilted or heelengaging relation with the bed 14, as shown in full lines in FIG. 4, andthen full bed engagement as indicated by dash lines. Though not here soshown, it will be understood that the control circuit being describedalso preferably acts simultaneously to initiate operation of the machine10.

Fluid pressure line 52 (FIG. 2) from the fluid amplifier 46 alsoinitiates a time delay unit 54 and actuates a valve 56 to allow fluidpressure to be admitted via a line 58 to a cylinder 60 (FIGS. l-3) foroperating an auxiliary, spring-retum presser finger 62 next to bedescribed. It may preliminarily be explained with reference to FIG. 3that the left and now leading edge of the work W will, when firsthemmed, lie between the feed dog 18 and the raised presser foot toe end30. Hand presentation of the work to the hemmers, if employed, may alsourge the leading work edge sufficiently leftward to enable it to comeunder the pulling influence of the presser foot and the feed dog, or thehemmers may be slightly angularly disposed when desirable to bias theleft edge into the feeding zone of the dog 18. As the needle 16 and feeddog 18 commence operation it is desirable that the plies of the hem beuniformly advanced without slippage and that the considerable frictionprovided by the work folds in the hemmers 34, 36 be overcome positively.The presser finger 62, preferably fitted with a rubber tip 66 to avoidrebound, yieldably forces the presser foot into work-engaging positionparallel with the bed 14, the underside of the presser foot at oncecausing the work to be gripped effectively and hence fed by theoperation of the dog 18. The cylinder 60 is adjustably mounted to directits piston rod, functioning as the presser finger 62 referred to,downwardly against any selected portion of the presser foot 20. For thispurpose a bracket 64 (FIGS. 1 and 3) has a forked end adjustably clampedto the cylinder 60 and an opposite mounting end extending into, andadjustable about the horizontal axis of, a bore formed in the bracket26.

After an initial interval of engagement of the presser foot tip 66 withthe presser foot toe 30, usually sufficient to efiect l or 2 inches offeeding, the unit 54 times out the finger 62 is retracted as pressure tothe cylinder 60 is cut off by the valve 66. Nonnal feeding operationthen proceeds until the hem H has been completely secured.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

1. In a sewing machine having stitch forming instrumentalities and workfeeding mechanism for advancing a work piece over a work support to theoperating zone of said instrumentalities, the feeding mechanismincluding two cooperative work-engaging members one of which isyieldingly movable to urge the work into clamping relation with theother member, the improvement which comprises a presser engageable withthe yieldingly movable member to urge it more firmly toward the othermember, and means for more intensively operating the presser during atleast an initial interval as the work is fed between the members therebyincreasing the effectiveness of the feeding mechanism.

2. A sewing machine as set forth in claim 1 wherein said cooperativemembers are an orbital feed dog and a presser foot, and said presser isin the form of a fluid pressure operated piston rod engageable with thepresser foot.

3. A machine as set forth in claim 2 wherein the presser foot is carriedby a downwardly urged bar, and a cylinder for actuating the piston rodis adjustably connected to said bar to enable a selected portion of the,presser foot to be engaged by the piston rod.

4. A machine as set forth in claim 1 wherein a control circuit operableto start the machine includes a timing unit for maintaining the presserin engagement with the presser foot for a predetermined interval only ofthe feeding.

5. In combination with a sewing machine having a reciprocable needle, abed, and work feeding means including a feed'dog and cooperative presserfoot for feeding the work on the bed to and through the stitching zoneof the needle, said presser foot being pivotally mounted on a baryieldingly urged toward the bed and having spring means for urging thepresser foot toe portion upwardly from the bed, hemming means mounted toreceive and form a margin of the work disposed ahead of the needle, apresser finger engageable with the presser foot toe portion, and acontrol circuit forstarting the machine and actuating said presserfinger when the hem has been formed whereby the presser finger enablesthe feeding means to advance the hem parallel to its marginal edge andtoward said zone.

# I t t t

1. In a sewing machine having stitch forming instrumentalities and workfeeding mechanism for advancing a work piece over a work support to theoperating zone of said instrumentalities, the feeding mechanismincluding two cooperative work-engaging members one of which isyieldingly movable to urge the work into clamping relation with theother member, the improvement which comprises a presser engageable withthe yieldingly movable member to urge it more firmly toward the othermember, and means for more intensively operating the presser during atleast an initial interval as the work is fed between the members therebyincreasing the effectiveness of the feeding mechanism.
 2. A sewingmachine as set forth in claim 1 wherein said cooperative members are anorbital feed dog and a presser foot, and said presser is in the form ofa fluid pressure operated piston rod engageable with the presser foot.3. A machine as set forth in claim 2 wherein the presser foot is carriedby a downwardly urged bar, and a cylinder for actuating the piston rodis adjustably connected to said bar to enable a selected portion of thepresser foot to be engaged by the piston rod.
 4. A machine as set forthin claim 1 wherein a control circuit operable to start the machineincludes a timing unit for maintaining the presser in engagement withthe presser foot for a predetermined interval only of the feeding.
 5. Incombination with a sewing machine having a reciprocable needle, a bed,and work feeding means including a feed dog and cooperative presser footfor feeding the work on the bed to and through the stitching zone of theneedle, said presser foot being pivotally mounted on a bar yieldinglyurged toward the bed and havinG spring means for urging the presser foottoe portion upwardly from the bed, hemming means mounted to receive andform a margin of the work disposed ahead of the needle, a presser fingerengageable with the presser foot toe portion, and a control circuit forstarting the machine and actuating said presser finger when the hem hasbeen formed whereby the presser finger enables the feeding means toadvance the hem parallel to its marginal edge and toward said zone.